![which of the following provides a measure of the average speed of air molecules? which of the following provides a measure of the average speed of air molecules?](https://venturebeat.com/wp-content/uploads/2020/05/BLOG_GIF_-_SIMULTANEOUS.gif)
The most popular positioning methods include the RTK technique and the increasingly common Real Time Network (RTN) technique. They offered either paid or free-of-charge real-time and post-processing services.
![which of the following provides a measure of the average speed of air molecules? which of the following provides a measure of the average speed of air molecules?](https://d2vlcm61l7u1fs.cloudfront.net/media%2F914%2F914167b1-491f-40eb-820f-4836ae31e82e%2Fphp1kZRvP.png)
In the early 21st century, GNSS geodetic networks became commonly launched by the geodetic authorities of individual countries. These include tests using Unmanned Aerial Vehicles (UAV) and Unmanned Surface Vehicles (USV), locating mobile phones, indoor, terrestrial and space navigation, geodetic and hydrographic surveys, operating Autonomous Ground Vehicles (AGV), rail transport, in particular for the purposes of High-Speed Rail (HSR), road transport or preventing intentional interference. Due to their extensive capabilities, GNSS/INS systems are primarily used in navigation and transport applications. GNSS/INS systems can be additionally supported by the operation of other devices, such as Light Detection And Ranging (LiDAR), odometers or vision sensors, in order to compensate for INS errors. GNSS systems: Global Positioning System (GPS), GLObal NAvigation Satellite System (GLONASS), BeiDou Navigation Satellite System (BDS) and Galileo, as well as Ground Based Augmentation Systems (GBAS) and Satellite Based Augmentation Systems (SBAS) in combination with inertial devices provided navigation solutions that, in the absence of access to satellite signals (in tunnels, confined spaces and forested areas), enable the continuous determination of a moving object’s position. Therefore, it can be expected that soon it will be used in all the IHO orders.
![which of the following provides a measure of the average speed of air molecules? which of the following provides a measure of the average speed of air molecules?](https://pubs.acs.org/na101/home/literatum/publisher/achs/journals/content/jpcafh/2021/jpcafh.2021.125.issue-23/acs.jpca.1c02864/20210611/images/medium/jp1c02864_0003.gif)
Statistical analyses showed that it was only a few centimetres away from meeting this criterion.
![which of the following provides a measure of the average speed of air molecules? which of the following provides a measure of the average speed of air molecules?](https://www.restek.com/globalassets/images/articles/figure-article-gnar3276-02.jpg)
Moreover, it was proven that the DGPS system does not only meet the requirements provided for the most stringent IHO order, i.e., the Exclusive Order (horizontal position error ≤ 1 m ( p = 0.95)). Tests have confirmed that the RTK system meets the requirements of all the IHO orders, even in situations where it is not functioning 100% properly. The model was verified taking into account the historical and current test results of the DGPS and RTK systems. The acquired data were processed using the mathematical model that allows us to assess whether any positioning system at a given point in time meets (or not) the accuracy requirements for each IHO order. GNSS/INS measurements were carried out during the manoeuvring of the Autonomous/Unmanned Surface Vehicle (ASV/USV) named “HydroDron” on Kłodno lake in Zawory. During the research, the following two INSs were used: Ekinox2-U and Ellipse-D by the SBG Systems, which were supported by DGPS and Real Time Kinematic (RTK) receivers. The aim of this article is to determine the usefulness of GNSS/Inertial Navigation Systems (INS) for hydrographic surveys. Due to the fact that a new order of hydrographic surveys has appeared in the IHO S-44 standard from 2020-Exclusive, looking at the current positioning accuracy of the DGPS system, it is not known whether it can be used in it. The Global Navigation Satellite System (GNSS) network solutions (accuracy: 2–3 cm ( p = 0.95)) and the Differential Global Positioning System (DGPS) (accuracy: 1–2 m ( p = 0.95)) are now commonly used positioning methods in hydrography. They are as follows, respectively: 1, 2, 5, 5 and 20 m, with a confidence level of 95% in two-dimensional space. Hydrographic surveys, in accordance with the International Hydrographic Organization (IHO) S-44 standard, can be carried out in the following five orders: Exclusive, Special, 1a, 1b and 2, for which minimum accuracy requirements for the applied positioning system have been set out.